The unit cell for this seamless pattern can be had in Inkscape by selecting the rectangle and using shift+alt+i
Source Firkin
The original enhanced with some gradients.
Source Firkin
Abstract Arbitrary Geometric Background derived from an image on Pixabay.
Source GDJ
Recreated from a pattern found in 'Az Osztrák-Magyar Monarchia irásban és képben', 1882. To get the tile this is based on select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A seamless pattern the starting point for which was a 'colour modulo' texture in Paint.net.
Source Firkin
This was formed by distorting an image of a background on Pixabay.
Source Firkin
You don’t see many mid-tone patterns here, but this one is nice.
Source Joel Klein
This is the third pattern called Dark Denim, but hey, we all love them!
Source Brandon Jacoby
Prismatic Geometric Pattern Background 2 No Black
Source GDJ
This metal background pattern resembles a metal plate with rivets. Solid rivets on a metal plate.
Source V. Hartikainen
Tweed is back in style – you heard it here first. Also, the @2X version here is great!
Source Simon Leo
This is a semi-dark pattern, sort of linen-y.
Source Sagive SEO
Alternative colour scheme to the original.
Source Firkin
A seamless pattern formed from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
Zerro CC tillable texture of stones photographed and made by me. CC0
Source Sojan Janso
A car pattern?! Can it be subtle? I say yes!
Source Radosław Rzepecki
This is a seamless pattern of regular hexagon which has a honeycomb structure.
Source Yamachem
The tile this is based on can be retrieved by selecting the rectangle in Inkscape and using shift+alt+i.
Source Firkin
Based on several public domain drawings on Wikimedia Commons. This was formed from a rectangular tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
Prismatic Basic Pattern 2 No Background
Source GDJ